A window assembly generally includes a window frame, at least one sash, and a pair of opposing window jambs with each jamb having a channel for allowing the vertical travel of the sash. The sash is attached to a balance which assists with the raising and lowering of the sash by providing a force to counterbalance the weight of the sash.
The jambs are part of the window frame and are positioned on either side of the sash. The jamb channels must provide adequate clearance to permit the sash support, also known as a carrier, to freely traverse up and down within them. The movement of the sash with respect to a fixed spring assembly causes friction and can damage internal surfaces within the channel. This permits detritus from the damaged channel to flow through the jamb channel to impair the movement of the sash and interfere with a spring support mechanism.
Windows are subject to manufacturing guidelines that specify air flow standards for various designs. For example, there are a variety of standards which apply depending upon the region of the country to which the window is to be shipped for installation. Not only must the sash panes be able to structurally withstand high air pressures, but the various moving elements of each window frame must be able to move freely.
Previous attempts to alleviate the problem with springs and counterbalance assemblies within the jamb channels of window frames have failed to achieve the desired result. What is needed is a structure that successfully achieves the goal of reducing the amount of interaction between the spring and sash that is within a jamb channel. This objective preferably would be achieved while not increasing friction which might add to the burden of moving the sash up and down through the jamb channel.